Sonenclar laughed off comments from judges Simon Cowell and Demi Lovato questioning her age while wearing a long, chiffon gown and looking considerably more mature than in previous weeks.

"You're 13 years old? Then I don't believe that you're a human being," Cowell said. "Because you can't do that at 13. Your control on that song ... and that note at the end was absolutely incredible."

Lovato even groaned at Sonenclar's talent. "Ugh, you are so good," she said. "And it honestly just doesn't make sense."

"I don't believe that that's your voice," Lovato went on. "I feel like Celine Dion is here and she's hiding." To which Sonenclar shook her head and said no with a laugh.

Judge L.A. Reid, who mentors two of the top three vote-getters from last week – Sonenclar was No. 2 – went so far as to say Sonenclar could walk away with the top prize, a $5 million recording contract. "I don't want to say this but we could be looking at the winner," Reid said to Britney Spears, Sonenclar's "mentor" on the show.

Spears laughed and nodded to Reid, mouthing, "I think so." Spears also said that Sonenclar’s performance gave her chills.

After her performance, Sonenclar’s parents, Bob and Terri, stood off stage and exchanged hugs and kisses.

Leading into her performance, Sonenclar told "X Factor" that it meant a lot to see her dad after being apart during her time on the show.

"He recorded a lot of me singing," Sonenclar said, referring to home videos her dad recorded when she was a toddler. "I was singing for my dad. Now, I'm singing in front of America."